Oncocytic-type intraductal papillary mucinous neoplasm (IPMN), first identified by Ohhashi et al. [4] in 1992 and first recognized by the World Health Organization (WHO) in 1996, is characterized by the presence of mucin-producing epithelial cells and cystic dilation in the pancreatic ducts. The gene discussed is MUC5AC; the disease is pancreatic intraductal papillary-mucinous neoplasm.